Efforts will be made to synthesize artificial peptides resembling elastin cross-links and to use these as hapten-immunogens for the puppose of raising antibodies to elastin and developing immune assays for elastin-degradation fragments. 2. Studies will be initiated on the stimuli responsibile for elastase-secretion by cultured alveolar macrphages of smokers, and efforts will be made to purify and characterize alveolar macrophage elastase. 3. Studies (in collaboration with Dr. R. King) will be continued on the hydrolysis of surfactant proteins by leukocyte proteases, and on the effects of such reactions on surface activity of lung surfactant. 4. Studies will be continued on the suppression of serum and lung antiproteases by oxidants in cigarette smoke. 5. Studies will be continued on the induction of alpha 1-antitrypsin synthesis in cultured liver cells by peptide fragments formed during the interaction of alpha 1-antitrypsin with elastase. 6. Studies will be continued on the identification of free leukyocyte protease in human lung connective tissues using immunohistochemical methods.